Proximal CD and long-term quality of life

What is known

• The Korean CONNECT cohort found proximal small-bowel involvement predicted inferior surgery-free survival but explicitly stated QoL was not assessed and should be evaluated in a future study. ¹
• L4 proximal disease is heterogeneous: EGD, jejunal, and proximal-ileal involvement carry different prognoses, with jejunal disease specifically linked to poor prognosis, so 'proximal' is not a single phenotype. ^2,3
• The endpoints in these proximal-disease cohorts are surgery, hospitalization, and disease behavior, not validated long-term QoL instruments. ^1–3

What is unknown / caveats

• Proximal-disease cohorts report worse surgical/prognostic outcomes, but none translate that into a measured QoL difference
• No retrieved study uses a validated QoL instrument to compare proximal vs distal disease
• 'proximal/L4' pools heterogeneous EGD, jejunal and proximal-ileal subgroups, confounding any location-QoL claim
• The QoL instruments in the corpus (SF-36, IBDQ, EuroQol) appear only in a methods review, not applied to this comparison
• Whether proximal disease independently worsens long-term QoL cannot be answered from the retrieved cohorts because they did not measure it.

References

1. Kim OZ, Han DS, Park CH, Eun CS, Kim YS, Kim YH, Cheon JH, Ye BD, Kim JS. The Clinical Characteristics and Prognosis of Crohn's Disease in Korean Patients Showing Proximal Small Bowel Involvement: Results from the CONNECT Study. Gut Liver. 2018. PMID: 28798284.

2. Mao R, Tang RH, Qiu Y, Chen BL, Guo J, Zhang SH, Li XH, Feng R, He Y, Li ZP, Zeng ZR, Eliakim R, Ben-Horin S, Chen MH. Different clinical outcomes in Crohn's disease patients with esophagogastroduodenal, jejunal, and proximal ileal disease involvement: is L4 truly a single phenotype?. Ther Adv Gastroenterol. 2018. PMID: 29899757.

3. Lazarev M, Huang C, Bitton A, Cho JH, Duerr RH, McGovern DP, Proctor DD, Regueiro M, Rioux JD, Schumm PP, Taylor KD, Silverberg MS, Steinhart AH, Hutfless S, Brant SR. Relationship between proximal Crohn's disease location and disease behavior and surgery: a cross-sectional study of the IBD Genetics Consortium. Am J Gastroenterol. 2013. PMID: 23229423.

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Draft, generated by the IBDology RAG and not yet clinician-reviewed. Answers are grounded in the retrieved literature listed above; a high faithfulness score means the answer matches its sources, not that the sources are correct.